MEDICAL Q&A: Cholesterol is vital to your good health

Q: How important is my cholesterol level to my heart health? What should I eat to lower my cholesterol?

A: Confusion about this much-maligned substance is common, even among the scientists who study it

“People talk and write about cholesterol as ‘artery-clogging fat,’ ” says cardiologist Dariush Mozaffarian, an associate professor of medicine and epidemiology at Harvard Medical School. “But this idea that you eat something, it gets into your bloodstream and it clogs your arteries is just false. Nothing remotely like that is happening.”

In fact, most of the cholesterol in your body doesn’t come from food — it’s made by the body itself. The liver produces this waxy, fatlike substance, which is just one component — along with calcium and other debris — of the plaque that can clog arteries and cause heart attacks and certain kinds of stroke.

But most of the time, cholesterol isn’t there to cause trouble; it travels through the bloodstream doing a number of important jobs. It helps make key hormones such as estrogen and testosterone, synthesize vitamin D, and build and maintain cell membranes, all of which are “absolutely mandatory” for good health, says Michael Blaha, director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease.

To transport and store cholesterol, the liver packages it into lipoproteins — particles that are part fat and part protein. Lowdensity lipoproteins (LDL) carry cholesterol to the body’s cells; high-density lipoproteins (HDL) bring it back to the liver, where it gets recycled or excreted. Cholesterol tests, or “lipid panels,” measure the levels of lipoproteins circulating in the blood, along with triglycerides — fats often packaged with lipoproteins.

In a healthy cardiovascular system, LDL, HDL and triglycerides are in balance. Until recently, physicians focused on the total cholesterol level. But looking at just one number doesn’t account for the interplay among LDL, HDL and triglycerides, or the fact that each of these affects risk in a different way, Mozaffarian says.

Although the research is complex, the gist of it is simple, says Michael Blaha, director of clinical research at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease: “HDL is good — the more you have, the lower your risk of heart disease. Everything else, you want to keep the levels low.”

Specifically, the National Heart, Lung, and Blood Institute recommends a total cholesterol level of less than 200 milligrams per deciliter of blood, an LDL level of less than 100 mg/dL and an HDL level over 60 mg/dL for optimal health. Optimal triglyceride levels should come in below 100 mg/dL.

Reaching cholesterol goals

Researchers agree about some of the ways to reach these goals: Losing weight, quitting smoking and exercising have all been linked to more optimal cholesterol levels and lower heart disease risk.

But there is some disagreement over which dietary changes are best for heart health, says Roger Blumenthal, director of the Ciccarone Center.
“For most people, cholesterol from food isn’t a contributor to their cholesterol levels,” Blumenthal says.

A 2014 study co-authored by Mozaffarian that analyzed data from 76 studies involving more than 600,000 participants found scant evidence to support recommendations that people avoid saturated fat — the kind found in such foods as red meat, butter and cheese, long vilified as bad for heart health.

“Basically, foods are more than just the cholesterol or just the fat in them,” Mozaffarian says. “We need to eat healthy, minimally processed foods overall — especially plants and olive oil and nuts — and not define those foods by the nutrients they have or lack.”

– Gisela Telis

Last modified: July 15, 2014
All rights reserved. This copyrighted material may not be published without permissions. Links are encouraged.